MPH conversions
Thread Starter
Melting Slicks
Joined: Nov 2000
Posts: 2,469
Likes: 6
From: Winchester Ontario
MPH conversions
Do you know of a chart where I can quick reference what the MPH should be (+/- a bit) on any given ET?
Like, if a car runs the 1/8 in 8.5 @ 85 MPH, what MPH would it run if it ran a 8.0? a 7.5?
I have found 1/8 to 1/4 ET comparisons, but I want to see what the MPH would be if I changed the ET's.
Like, if a car runs the 1/8 in 8.5 @ 85 MPH, what MPH would it run if it ran a 8.0? a 7.5?
I have found 1/8 to 1/4 ET comparisons, but I want to see what the MPH would be if I changed the ET's.
Le Mans Master
Joined: Aug 1999
Posts: 7,338
Likes: 137
From: WilkesBarre PA
I can't see how there could be one. So many cars run such differant ETs vs. MPH. One car may run a 11.00@110 where another may only run a 12.00@110 depending on chasis setups. But there prolly is one someone made up like all the others.
Race Director
Joined: Jan 2003
Posts: 15,172
Likes: 86
From: State of Confusion
black_89_vette:
"Back-in-the-day", racers used something called a 'hook-factor' to judge ET vs. MPH, based-on their time-slip.
In a nut-shell, ET x MPH (in the 1/4-mile) = the 'hook-factor', and racers tried to get this 'factor as close to '1320' as possible.
A 'hook-factor' well-over 1320 meant the car needed traction help, or more gearing, and numbers below 1320 probably meant the car had too-much gearing already.
While I never heard of 1/8-mile racers using a modified 'hook-factor', when I raced 1/8-mile weekly, I remember my 'factor' was between 680-700.
Looking-over recent, 1/4-mile time-slips, this seems to be correct. For instance, I'd run 12.85 @ 105 (1349), and my 1/8-mile 'factor' was '698' (8.21 @ 85).
Just-for-laughs, I think you could take '700', and divide it by a 'proposed' ET to have a 'guesstimate' of your MPH.
Example: 700 div/by 8.0 = 87.5; 700 div/by 7.5 = 93+; etc.
Again, your estimeted 1/8-mile 'factor' can fluctuate higher/lower, based-on gearing, traction, etc.
Going from memory of my old opponents, these MPH at those ET 'sound-about-right'...
"Back-in-the-day", racers used something called a 'hook-factor' to judge ET vs. MPH, based-on their time-slip.
In a nut-shell, ET x MPH (in the 1/4-mile) = the 'hook-factor', and racers tried to get this 'factor as close to '1320' as possible.
A 'hook-factor' well-over 1320 meant the car needed traction help, or more gearing, and numbers below 1320 probably meant the car had too-much gearing already.
While I never heard of 1/8-mile racers using a modified 'hook-factor', when I raced 1/8-mile weekly, I remember my 'factor' was between 680-700.
Looking-over recent, 1/4-mile time-slips, this seems to be correct. For instance, I'd run 12.85 @ 105 (1349), and my 1/8-mile 'factor' was '698' (8.21 @ 85).
Just-for-laughs, I think you could take '700', and divide it by a 'proposed' ET to have a 'guesstimate' of your MPH.
Example: 700 div/by 8.0 = 87.5; 700 div/by 7.5 = 93+; etc.
Again, your estimeted 1/8-mile 'factor' can fluctuate higher/lower, based-on gearing, traction, etc.
Going from memory of my old opponents, these MPH at those ET 'sound-about-right'...
Team Owner
Joined: Jul 2003
Posts: 20,474
Likes: 2
From: Detroit
Your not going to find anything accurate IMHO. Every car pulls differently. My car for example ( even before the blower ) pulled *very* strong up high. My 60 foots stunk ( stock run-flat tires ).
Mark
Mark
Race Director
Joined: Jan 2003
Posts: 15,172
Likes: 86
From: State of Confusion
Originally Posted by black_89_vette
Can everyone post their 1/8 and 1/4 ET's and MPH's that is close to the 7.5 - 8.0 seconds in the 1/8 mile.
here are some of the ET/MPH figures recorded from opponents time-runs and/or red-light elimination passes (no 'lifting', for fear of breaking-out):
8.226 @ 83.42 (686)
8.112 @ 85.16 (690)
8.032 @ 86.30 (693)
7.911 @ 85.24 (674)
7.847 @ 85.71 (672)
7.776 @ 88.28 (686)
7.676 @ 88.11 (676)
7.636 @ 90.65 (692)
7.596 @ 89.61 (680)
7.532 @ 90.05 (678)
Based on my records, and memory of these opponents, the cars that factor 690+ (like mine), were set-up to run 1/4-mile, too;
most of the cars factoring 680 and lower were 1/8-mile only cars (much deeper gearing).
Le Mans Master
Joined: Feb 2004
Posts: 5,482
Likes: 1
From: Living the Taxation Dream Indiana
These numbers are stock and then after the Stinger Intake install, and I am still on the run-flats. These are of course 1/8 mile times 
9.04@80.31
9.14@79.79
8.87@82.04
8.93@82.59
9.00@80.45 (2 people in the car
)
9.04@80.31
9.14@79.79
8.87@82.04
8.93@82.59
9.00@80.45 (2 people in the car
)
